History and Role of Plant Breeding in Society

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1 History and role of plant breeding in society

Purpose and expected outcomes

Agriculture is the deliberate planting and harvesting of plants and herding animals. This human invention has, and continues to, impact on society and the environment. Plant breeding is a branch of agriculture that focuses on manipulating plant heredity to develop new and improved plant types for use by society. People in society are aware and appreciative of the enormous diversity in plants and plant products. They have preferences for certain varieties of ﬂowers and food crops. They are aware that whereas some of this variation is natural, humans with special expertise (plant breeders) create some of it. Generally, also, there is a perception that such creations derive from crossing different plants. The tools and methods used by plant breeders have been developed and advanced through the years. There are milestones in plant breeding technology as well as accomplishments by plant breeders over the years. This introductory chapter is devoted to presenting a brief overview of plant breeding, including a brief history of its development, how it is done, and its beneﬁts to society. After completing this chapter, the student should have a general understanding of:

1 The historical perspectives of plant breeding. 2 The need and importance of plant breeding to society. 3 The goals of plant breeding. 4 Trends in plant breeding as an industry. 5 Milestones in plant breeding. 6 The accomplishments of plant breeders. 7 The future of plant breeding in society.

What is plant breeding? goals of plant breeding are focused and purposeful. Even though the phrase “to breed plants” often con- Plant breeding is a deliberate effort by humans to nudge notes the involvement of the sexual process in effecting a nature, with respect to the heredity of plants, to an desired change, modern plant breeding also includes the advantage. The changes made in plants are permanent manipulation of asexually reproducing plants (plants and heritable. The professionals who conduct this task that do not reproduce through the sexual process). are called plant breeders. This effort at adjusting the Breeding is hence about manipulating plant attributes, status quo is instigated by a desire of humans to improve structure, and composition, to make them more use- certain aspects of plants to perform new roles or enhance ful to humans. It should be mentioned at the onset that existing ones. Consequently, the term “plant breeding” it is not every plant character or trait that is amenable is often used synonymously with “plant improvement” to manipulation by breeders. However, as techno- in modern society. It needs to be emphasized that the logy advances, plant breeders are increasingly able to POPC01 28/8/06 4:02 PM Page 4

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accomplish astonishing plant manipulations, needless to consumption of nutrient-deficient foods, as obtains in say not without controversy, as is the case involving the many developing regions where staple foods (e.g., rice, development and application of biotechnology to plant cassava) often lack certain essential amino acids or nutri- genetic manipulation. One of the most controversial of ents. Plant breeders may also target traits of industrial these modern technologies is transgenesis, the techno- value. For example, fiber characteristics (e.g., strength) logy by which gene transfer is made across natural bio- of fiber crops such as cotton can be improved, while oil logical barriers. crops can be improved to yield high amounts of specific Plant breeders specialize in breeding different groups fatty acids (e.g., the high oleic content of sunflower of plants. Some focus on field crops (e.g., soybean, cot- seed). The latest advances in technology, specifically ton), horticultural crops (e.g., vegetables), ornamentals, genetic engineering technologies, are being applied to fruit trees (e.g., citrus, apple), forage crops (e.g., alfalfa, enable plants to be used as bioreactors to produce grasses), or turf species. More importantly, breeders certain pharmaceuticals (called biopharming or simply tend to focus on specific species in these groups. This pharming). way, they develop the expertise that enables them to be The technological capabilities and needs of societies most effective in improving the species of their choice. of old, restricted plant breeders to achieving modest The principles and concepts discussed in this book are objectives (e.g., product appeal, adaptation to produc- generally applicable to breeding all species. However, tion environment). It should be pointed out that these most of the examples supplied are from breeding “older” breeding objectives are still important today. field crops. However, with the availability of sophisticated tools, plant breeders are now able to accomplish these genetic alterations in novel ways that are sometimes the Goals of plant breeding only option, or are more precise and more effective. Furthermore, as previously indicated, they are able to The plant breeder uses various technologies and undertake more dramatic alterations that were imposs- methodologies to achieve targeted and directional ible to attain in the past (e.g., transferring a desirable changes in the nature of plants. As science and techno- gene from a bacterium to a plant!). Some of the reasons logy advance, new tools are developed while old ones are why plant breeding is important to society are summar- refined for use by breeders. Before initiating a breeding ized next. project, clear breeding objectives are defined based on factors such as producer needs, consumer preferences and needs, and environmental impact. Breeders aim to Concept of genetic manipulation of make the crop producer’s job easier and more effective plant attributes in various ways. They may modify plant structure so it can resist lodging and thereby facilitate mechanical The work of Gregor Mendel and the further advances harvesting. They may develop plants that resist pests in science that followed his discoveries established that so the farmer does not have to apply pesticides or can plant characteristics are controlled by hereditary factors apply smaller amounts of these chemicals. Not applying or genes that consist of DNA (deoxyribose nucleic acid, pesticides in crop production means less environmental the hereditary material). These genes are expressed in an pollution from agricultural sources. Breeders may also environment to produce a trait. It follows then that in develop high-yielding varieties (or cultivars) so the order to change a trait or its expression, one may change farmer can produce more for the market to meet the nature or its genotype, and/or modify the nurture consumer demands while improving his or her income. (environment in which it is expressed). Changing the The term cultivar is reserved for variants deliberately environment essentially entails modifying the grow- created by plant breeders and will be introduced more ing or production conditions. This may be achieved formally later in the book. It will be the term of choice through an agronomic approach, for example, the appli- in this book. cation of production inputs (e.g., fertilizers, irrigation). When breeders think of consumers, they may, for Whereas this approach is effective in enhancing certain example, develop foods with higher nutritional value traits, the fact remains that once these supplemental and that are more flavorful. Higher nutritional value environmental factors are removed, the expression of means reduced illnesses in society (e.g., nutritionally the plant trait reverts to the status quo. On the other related ones such as blindness or ricketsia) caused by the hand, plant breeders seek to modify plants with respect POPC01 28/8/06 4:02 PM Page 5

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to the expression of certain attributes by modifying the pro-vitamin A (the precursor of vitamin A). The genotype (in a desired way by targeting specific genes). “Golden Rice” project, currently underway at the Such an approach produces an alteration that is perman- International Rice Research Institute (IRRI) in the ent (i.e., transferable from one generation to the next). Philippines and other parts of the world, is geared towards developing, for the first time ever, a rice cultivar with the capacity to produce pro-vitamin A. An Why breed plants? estimated 800 million people in the world, including 200 million children, suffer chronic undernutrition, with The reasons for manipulating plant attributes or perfor- its attendant health issues. Malnutrition is especially mance change according to the needs of society. Plants prevalent in developing countries. provide food, feed, fiber, pharmaceuticals, and shelter Breeding is also needed to make some plant products for humans. Furthermore, plants are used for aesthetic more digestible and safer to eat by reducing their toxic and other functional purposes in the landscape and components and improving their texture and other indoors. qualities. A high lignin content of the plant material reduces its value for animal feed. Toxic substances occur in major food crops, such as alkaloids in yam, cynogenic Addressing world food, feed, and nutritional needs glucosides in cassava, trypsin inhibitors in pulses, and Food is the most basic of human needs. Plants are the steroidal alkaloids in potatoes. Forage breeders are inter- primary producers in the ecosystem (a community of ested, among other things, in improving feed quality living organisms including all the non-living factors (high digestibility, high nutritional profile) for livestock. in the environment). Without them, life on earth for higher organisms would be impossible. Most of the Addressing food needs for a growing world crops that feed the world are cereals (Table 1.1). Plant population breeding is needed to enhance the value of food crops, by improving their yield and the nutritional quality of In spite of a doubling of the world population in the their products, for healthy living of humans. Certain last three decades, agricultural production rose at an plant foods are deficient in certain essential nutrients adequate rate to meet world food needs. However, an to the extent that where these foods constitute the bulk additional 3 billion people will be added to the world of a staple diet, diseases associated with nutritional population in the next three decades, requiring an deficiency are often common. Cereals tend to be low in expansion in world food supplies to meet the projected lysine and threonine, while legumes tend to be low in needs. As the world population increases, there would cysteine and methionine (both sulfur-containing amino be a need for an agricultural production system that is acids). Breeding is needed to augment the nutritional apace with population growth. Unfortunately, arable quality of food crops. Rice, a major world food, lacks land is in short supply, stemming from new lands that have been brought into cultivation in the past, or sur- rendered to urban development. Consequently, more Table 1.1 The 25 major food crops of the world, ranked food will have to be produced on less land. This calls for according to total tonnage produced annually. improved and high-yielding varieties to be developed by 1 Wheat 11 Sorghum 21 Apple plant breeders. With the aid of plant breeding, the yields 2 Rice 12 Sugarcane 22 Yam of major crops have dramatically changed over the years. 3 Corn 13 Millet 23 Peanut Another major concern is the fact that most of the popu- 4 Potato 14 Banana 24 Watermelon lation growth will occur in developing countries where 5 Barley 15 Tomato 25 Cabbage food needs are currently most serious, and where 6 Sweet potato 16 Sugar beet resources for feeding people are already most severely 7 Cassava 17 Rye strained, because of natural or human-made disasters, or 8 Grape 18 Orange ineffective political systems. 9 Soybean 19 Coconut 10 Oat 20 Cottonseed oil The need to adapt plants to environmental stresses Source: J.R. Harlan. 1976. Plants and animals that nourish man. In: Food and agriculture, A Scientific American Book. W.H. Freeman The phenomenon of global climatic change that is and Company, San Francisco. occurring over the years is partly responsible for POPC01 28/8/06 4:02 PM Page 6

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modifying the crop production environment (e.g., some meant for the table are different from those used in the regions of the world are getting drier and others saltier). food processing industry. For example, there are table This means that new cultivars of crops need to be bred grapes and grapes bred for wine production. One of for new production environments. Whereas developed the reasons why the first genetically modified (GM) economies may be able to counter the effects of un- crop (produced by using genetic engineering tools to seasonable weather by supplementing the production incorporate foreign DNA) approved for food, the environment (e.g., by irrigating crops), poor countries FlavrSavr® tomato, did not succeed was because the are easily devastated by even brief episodes of adverse product was marketed as a table or fresh tomato, when weather conditions. For example, the development and in fact the gene of interest was placed in a genetic back- use of drought-resistant cultivars is beneficial to crop ground for developing a processing tomato variety. production in areas of marginal or erratic rainfall Other factors contributed to the demise of this historic regimes. Breeders also need to develop new plant types product. Different markets have different needs that that can resist various biotic (diseases, insect pests) and plant breeders can address in their undertakings. For other abiotic (e.g., salt, drought, heat, cold) stresses in example, the potato is a versatile crop used for food the production environment. Crop distribution can be and industrial products. Different varieties are bred for expanded by adapting crops to new production environ- baking, cooking, fries (frozen), chipping, and starch. ments (e.g., adapting tropical plants to temperate These cultivars differ in size, specific gravity, and sugar regions). The development of photoperiod-insensitive content, among other properties. A high sugar content crop cultivars would allow the expansion in production is undesirable for frying or chipping because the sugar of previously photoperiod-sensitive species. caramelizes under high heat to produce undesirable browning of fries and chips. The need to adapt crops to specific production systems Plant breeding through the ages Breeders need to produce plant cultivars for different production systems to facilitate crop production and Plant breeding as a conscious human effort has ancient optimize crop productivity. For example, crop cultivars origins. must be developed for rain-fed or irrigated production, and for mechanized or non-mechanized production. In Origins of agriculture and plant breeding the case of rice, separate sets of cultivars are needed for upland production and for paddy production. In In its primitive form, plant breeding started after the organic production systems where pesticide use is highly invention of agriculture, when people of primitive cul- restricted, producers need insect- and disease-resistant tures switched from a lifestyle of hunter-gatherers to cultivars in crop production. sedentary producers of selected plants and animals. Views of agricultural origins range from the mytholo- gical to ecological. This lifestyle change did not occur Developing new horticultural plant varieties overnight but was a gradual process during which The ornamental horticultural production industry plants were transformed from being independent, wild thrives on the development of new varieties through progenitors, to fully dependent (on humans) and plant breeding. Aesthetics is of major importance to domesticated varieties. Agriculture is generally viewed horticulture. Periodically, ornamental plant breeders as an invention and discovery. During this period, release new varieties that exhibit new colors and other humans also discovered the time-honored and most morphological features (e.g., height, size, shape). Also, basic plant breeding technique – selection, the art of breeders develop new varieties of vegetables and fruits discriminating among biological variation in a popula- with superior yield, nutritional qualities, adaptation, and tion to identify and pick desirable variants. Selection general appeal. implies the existence of variability. In the beginnings of plant breeding, the variabilities exploited were the natu- rally occurring variants and wild relatives of crop species. Satisfying industrial and other end-use requirements Furthermore, selection was based solely on the intui- Processed foods are a major item in the world food tion, skill, and judgment of the operator. Needless to supply system. Quality requirements for fresh produce say, this form of selection is practiced to date by farmers POPC01 28/8/06 4:02 PM Page 7

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in poor economies, where they save seed from the invaluable to modern plant breeding. In 1727, Louis best-looking plants or the most desirable fruit for plant- Leveque de Vilmorin of the Vilmorin family of seed ing the next season. These days, scientific techniques growers founded the Vilmorin Breeding Institute in are used in addition to the aforementioned qualities to France as the first institution dedicated to plant breed- make the selection process more precise and efficient. ing and the production of new cultivars. There, another Even though the activities described in this section still commonly used breeding technique – progeny are akin to some of those practiced by modern plant test (growing the progeny of a cross for the purpose breeders, it is not being suggested that primitive crop of evaluating the genotype of the parent) – was first producers were necessarily conscious of the fact that used to evaluate the breeding value of a single plant. they were nudging nature to their advantage as modern Selected milestones in plant breeding are presented in breeders do. Table 1.2.

Plant breeding past (pre-Mendelian) Plant breeding present (post-Mendelian) Whereas early plant breeders did not deliberately create Modern plant breeding depends on the principles of new variants, modern plant breeders are able to create genetics, the science of heredity to which Gregor new variants that previously did not occur in natural Mendel made some of its foundational contributions. populations. It is difficult to identify the true beginnings Mendel’s original work on the garden pea was published of modern plant breeding. However, certain early in 1865. It described how factors for specific traits are observations by certain individuals helped to lay the transmitted from parents to offspring and through foundation for the discovery of the modern principles of subsequent generations. His work was rediscovered plant breeding. It has been reported that archaeological in 1900, with confirmation by E. von Tschermak, C. records indicate that the Assyrians and Babylonians Correns, and H. de Vries. These events laid the founda- artificially pollinated date palm, at least 700 bc. R. J. tion for modern genetics. Mendel’s studies gave birth to Camerarius (aka Rudolph Camerer) of Germany is cred- the concept of genes (and the discipline of genetics), ited with first reporting sexual reproduction in plants factors that encode traits and are transmitted through in 1694. Through experimentation, he discovered that the sexual process to the offspring. Further, his work pollen from male flowers was indispensable to fertiliza- resulted in the formulation of the basic rules of heredity tion and seed development on female plants. His work that are called Mendel’s laws. was conducted on monoecious plants (both sexes occur One of the earliest applications of genetics to plant on separate parts of the plant, e.g., spinach and maize). breeding was made by the Danish botanist, Wilhelm However, it was Joseph Koelreuter who conducted Johannsen. In 1903, Johannsen developed the pure- the first known systematic investigations into plant line theory while working on the garden bean. His hybridization (crossing of genetically dissimilar parents) work confirmed an earlier observation by others that of a number of species, between 1760 and 1766. the techniques of selection could be used to produce Similarly, in 1717, Thomas Fairchild, an Englishman, uniform, true-breeding cultivars by selecting from conducted an interspecific cross (a cross between two the progeny of a single self-pollinated crop (through species) between sweet william (Dianthus berbatus) repeated selfing) to obtain highly homozygous lines and D. caryophyllis, to obtain what became known as (true breeding), which he later crossed. Previously, H. Fairchild’s sweet william. Another account describes Nilson had demonstrated that the unit of selection was an observation in 1716 by an American, Cotton Mather, the plant. The products of the crosses (called hybrids) to the effect that ears from yellow corn grown next to yielded plants that outperformed either parent with blue or red corn had blue and red kernels in them. This respect to the trait of interest (the concept of hybrid suggested the occurrence of natural cross-pollination. vigor). Hybrid vigor (or heterosis) is the foundation of Maize is one of the crops that has received extensive modern hybrid crop production programs. breeding and genetic attention in the scientific commun- In 1919, D. F. Jones took the idea of a single cross ity. As early as 1846, Robert Reid of Illinois was cred- further by proposing the double-cross concept, which ited with developing what became known as “Reid’s involved a cross between two single crosses. This tech- Yellow Dent”. The landmark work by Swedish botanist, nique made the commercial production of hybrid corn Carolus Linnaeus (1707–1778), which culminated in seed economical. The application of genetics in crop the binomial systems of classification of plants, is improvement has yielded spectacular successes over the POPC01 28/8/06 4:02 PM Page 8

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Table 1.2 Selected milestones in plant breeding

9000 bc First evidence of plant domestication in the hills above the Tigris river 3000 bc Domestication of all important food crops in the Old World completed 1000 bc Domestication of all important food crops in the New World completed 700 bc Assyrians and Babylonians hand pollinate date palms 1694 Camerarius of Germany first to demonstrate sex in plants and suggested crossing as a method to obtain new plant types 1716 Mather of USA observed natural crossing in maize 1719 Fairchild created first artificial hybrid (carnation × sweet william) 1727 Vilmorin Company of France introduced the pedigree method of breeding 1753 Linnaeus published Species plantarium. Binomial nomenclature born 1761–1766 Koelreuter of Germany demonstrated that hybrid offspring received traits from both parents and were intermediate in most traits; produced first scientific hybrid using tobacco 1847 “Reid’s Yellow Dent” maize developed 1866 Mendel published his discoveries in Experiments in plant hybridization, cumulating in the formulation of laws of inheritance and discovery of unit factors (genes) 1899 Hopkins described the ear-to-row selection method of breeding in maize 1900 Mendel’s laws of heredity rediscovered independently by Correns of Germany, de Vries of Holland, and von Tschermak of Austria 1903 The pure-line theory of selection developed 1904–1905 Nilsson-Ehle proposed the multiple factor explanation for inheritance of color in wheat pericarp 1908–1909 Hardy of England and Weinberg of Germany developed the law of equilibrium of populations 1908–1910 East published his work on inbreeding 1909 Shull conducted extensive research to develop inbreds to produce hybrids 1917 Jones developed first commercial hybrid maize 1926 Pioneer Hi-bred Corn Company established as first seed company 1934 Dustin discovered colchicines 1935 Vavilov published The scientific basis of plant breeding 1940 Harlan used the bulk breeding selection method in breeding 1944 Avery, MacLeod, and McCarty discovered DNA is hereditary material 1945 Hull proposed recurrent selection method of breeding 1950 McClintock discovered the Ac-Ds system of transposable elements 1953 Watson, Crick, and Wilkins proposed a model for DNA structure 1970 Borlaug received Nobel Prize for the Green Revolution Berg, Cohen, and Boyer introduced the recombinant DNA technology 1994 “FlavrSavr” tomato developed as first genetically modified food produced for the market 1995 Bt corn developed 1996 Roundup Ready® soybean introduced 2004 Roundup Ready® wheat developed

years, one of the most notable being the development accelerated after World War II, when scientists included of dwarf, environmentally responsive cultivars of wheat nuclear particles (e.g., alpha, protons, and gamma) as and rice for the subtropical regions of the world. These mutagens for inducing mutations in organisms. Even new plant materials transformed food production in though very unpredictable in outcome, mutagenesis has these regions in a dramatic fashion, and in the process been successfully used to develop numerous mutant became dubbed the Green Revolution. This remark- varieties. able achievement in food production is discussed below. In 1944, DNA was discovered to be the genetic mater- Mutagenesis (the induction of mutations using muta- ial. Scientists then began to understand the molecular genic agents (mutagens) such as radiation or chemicals) basis of heredity. New tools (molecular tools) are being became a technique for plant breeding in the 1920s developed to facilitate plant breeding. Currently, scien- when researchers discovered that exposing plants to X- tists are able to circumvent the sexual process to trans- rays increased the variation in plants. Mutation breeding fer genes from one parent to another. In fact, genes POPC01 28/8/06 4:02 PM Page 9

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can now be transferred from virtually any organism 160 to another. This newest tool, specifically called gen- Corn etic engineering, has its proponents and distracters. 140 Wheat Current successes include the development of insect Soybean resistance in crops such as maize by incorporating a gene 120 from the bacterium Bacillus thuringiensis. Cultivars 100 containing an alien gene for insect resistance from this particular organism are called Bt cultivars, diminutive of 80 the scientific name of the bacterium. The products of the application of this alien gene transfer technology are 60 Grain yield (bu/ac) generally called genetically modified (GM) or transgenic 40 products. Plant biotechnology, the umbrella name for the host of modern plant manipulation techniques, has 20 produced, among other things, molecular markers to 0 facilitate the selection process in plant breeding. 1950 1964 1972 1982 1992 2002 Year

Achievements of modern plant breeders Figure 1.1 The yield of major world food crops is steadily The achievements of plant breeders are numerous, but rising, as indicated by the increasing levels of crops may be grouped into several major areas of impact – produced in the US agricultural system. A signiﬁcant yield increase, enhancement of compositional traits, portion of this rise is attributable to the use of improved crop adaptation, and the impact on crop production crop cultivars by crop producers. bu/ac, bushels per acre. systems. Source: Drawn with data from the USDA.

produced for use in various parts of the world. For Yield increase example, different kinds of wheat are needed for dif- Yield increase in crops has been accomplished in a ferent kinds of products (e.g., bread, pasta, cookies, variety of ways including targeting yield per se or its semolina). Breeders have identified the quality traits components, or making plants resistant to economic associated with these uses and have produced cultivars diseases and insect pests, and breeding for plants that with enhanced expression of these traits. Genetic engin- are responsive to the production environment. Yields eering technology has been used to produce high oleic of major crops (e.g., corn, rice, sorghum, wheat, soy- sunflower for industrial use, while it is also being used to bean) have significantly increased in the USA over the enhance the nutritional value of crops (e.g., pro-vitamin years (Figure 1.1). For example, the yield of corn rose A “Golden Rice”). The shelf-life of fruits (e.g., tomato) from about 2,000 kg/ha in the 1940s to about 7,000 has been extended through the use of genetic engineer- kg/ha in the 1990s. In England, it took only 40 years ing techniques to reduce the expression of compounds for wheat yields to rise from 2,000 to 6,000 kg/ha. associated with fruit deterioration. These yield increases are not totally due to the genetic potential of the new crop cultivars but also due to Crop adaptation improved agronomic practices (e.g., application of fertilizer, irrigation). Crops have been armed with disease Crop plants are being produced in regions to which they resistance to reduce yield loss. Lodging resistance also are not native, because breeders have developed culti- reduces yield loss resulting from harvest losses. vars with modified physiology to cope with variations, for example, in the duration of day length (photoperiod). Photoperiod-insensitive cultivars will flower Enhancement of compositional traits and produce seed under any day length conditions. The Breeding for plant compositional traits to enhance duration of the growing period varies from one region nutritional quality or to meet an industrial need are of the world to another. Early maturing cultivars of crop major plant breeding goals. High protein crop varieties plants enable growers to produce a crop during a short (e.g., high lysine or quality protein maize) have been window of opportunity, or even to produce two crops in POPC01 28/8/06 4:02 PM Page 10

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one season. Furthermore, early maturing cultivars can The Green Revolution started in 1943 when the be used to produce a full season crop in areas where Mexican government and the Rockefeller Founda- adverse conditions are prevalent towards the end of the tion co-sponsored a project, the Mexican Agricultural normal growing season. Soils formed under arid condi- Program, to increase food production in Mexico. The tions tend to accumulate large amounts of salts. In order ﬁrst target crop was wheat, and the goal was to increase to use these lands for crop production, salt-tolerant wheat production by a large margin. Using an interdiscip- (saline and aluminum tolerance) crop cultivars have linary approach, the scientiﬁc team headed by Norman been developed for certain species. In crops such as Borlaug, a wheat breeder at the Rockefeller Foundation, barley and tomato, there are commercial cultivars in use, started to assemble genetic resources (germplasm) of with drought, cold, and frost tolerance. wheat from all over the world (East Africa, Middle East, South Asia, Western Hemisphere). The key genotypes used by Norman Borlaug in his breeding program were The Green Revolution the Japanese “Norin” dwarf genotypes supplied by Producing enough food to feed the world’s ever increas- Burton Bayles of the United States Department of

ing population has been a lingering concern of modern Agriculture (USDA) and a segregating (F2) population societies. Perhaps the most notable essay on food and of “Norin 10” crossed with “Brevor”, a Pacific population dynamics was written by Thomas Malthus in Northwest wheat, supplied by Orville Vogel of the 1798. In this essay, “Essay on the principles of popula- USDA. These introductions were crossed with indigen- tion”, he identified the geometric role of natural popu- ous (Mexican) wheat that had adaptability (to temper- lation increase in outrunning subsistence food supplies. ature, photoperiod) to the region and were disease He observed that unchecked by environmental or social resistant, but were low yielding and prone to lodging. constraints it appears that human populations double The team was able to develop lodging-resistant cultivars every 25 years, regardless of the initial population size. through introgression of dwarf genes from semidwarf Because population increase, according to this observa- cultivars from North America. This breakthrough tion, was geometric, whereas food supply at best was occurred in 1953. Further crossing and selection arithmetic, there was implicit in this theory pessimism resulted in the release of the first Mexican semidwarf about the possibility of feeding ever growing popula- cultivars, “Penjamo 62” and “Pitic 62”. Together with tions. Fortunately, mitigating factors such as techno- other cultivars, these two hybrids dramatically trans- logical advances, advances in agricultural production, formed wheat yields in Mexico, eventually making changes in socioeconomics, and political thinking of Mexico a major wheat exporting country. The success- modern society, has enabled this dire prophesy to ful wheat cultivars were introduced into Pakistan, India, remain unfulfilled. and Turkey in 1966, with similar results of outstanding Unfortunately, the technological advances in the performance. During the period, wheat production 20th century primarily benefited the industrial coun- increased from 300,000 to 2.6 million tons/year; yields tries, leaving widespread hunger and malnutrition to per unit area increased from 750 to 3,200 kg/ha. persist in most developing countries. Many of these The Mexican model (interdisciplinary approach, nations depend on food aid from industrial countries for international team effort) for agricultural transforma- survival. In 1967, a report by the US President’s Science tion was duplicated in rice in the Philippines in 1960. Advisory Committee came to the grim conclusion that This occurred at the IRRI. The goal of the IRRI team “the scale, severity and duration of the world food prob- was to increase productivity of rice in the field. Rice lem are so great that a massive, long-range, innovative germplasm was assembled. Scientists determined that, effort unprecedented in human history will be required like wheat, a dwarf cultivar that was resistant to lodging, to master it”. The Rockefeller and Ford Foundations, amenable to high density crop stand, responsive to fer- acting on this challenge, proceeded to establish the first tilization and highly efficient in partitioning of photo- international agricultural system to help transfer the synthates or dry matter to the grain, was the cultivar to agricultural technologies of the developed countries to breed. the developing countries. These humble beginnings led In 1966, the IRRI released a number of dwarf rice to a dramatic impact on food production in the third cultivars to farmers in the Philippines. The most success world, especially Asia, which would be dubbed the was realized with IR8, which was early maturing (120 Green Revolution, a term coined in 1968 by the USAID days), thus allowing double cropping in certain regions. Administrator, William S. Gaud. The key to the high yield of the IR series was their POPC01 28/8/06 4:02 PM Page 11

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Industry highlights Normal Ernest Borlaug: the man and his passion George Acquaah

Department of Agriculture and Natural Resources, Langston University, Langston, OK 73050, USA

For more than half a century, I have worked with the production of more and better wheat for feeding the hungry world, but wheat is merely a catalyst, a part of the picture. I am interested in the total development of human beings. Only by attacking the whole problem can we raise the standard of living for all people, in all communities, so that they will be able to live decent lives. This is something we want for all people on this planet. Norman E. Borlaug

Dr Norman E. Borlaug has been described in the literature in many ways, including as “the father of the Green Revolution”, “the forgotten benefactor of humanity”, “one of the greatest benefactors of human race in modern times”, and “a distinguished scientist-philosopher”. He has been presented before world leaders and received numerous prestigious academic honors from all over the world. He belongs to an exclusive league with the likes of Henry Kissinger, Elie Wiesel, and President Jimmy Carter – all Nobel Peace laureates. Yet, Dr Borlaug is hardly a household name in the USA. But, this is not a case of a prophet being without honor in his country. It might be more because this outstanding human being chooses to direct the spotlight on his passion, rather than his person. As previously stated in his own words, Dr Borlaug has a passion for helping to achieve a decent living status for the people of the world, starting with the alleviation of hunger. To this end, his theatre of operation is the third world countries, which are characterized by poverty, political instability, chronic food shortages, malnutrition, and the prevalence of preventable diseases. These places are hardly priority sources for news for the ﬁrst world media, unless an epidemic or cata- strophe occurs. Dr Borlaug was born on March 25, 1914, to Henry and Clara Borlaug, Norwegian immigrants in the city of Saude, near Cresco, Iowa. He holds a BS degree in Forestry, which he earned in 1937. He pursued an MS in Forest Pathology, and later earned a PhD in Pathology and Genetics in 1942 from the University of Minnesota. After a brief stint with the E. I. du Pont de Nemours in Delaware, Dr Borlaug joined the Rockefeller Foundation team in Mexico in 1944, a move that would set him on course to achieve one of the most notable accomplishments in history. He became the director of the Cooperative Wheat Research and Production Program in 1944, a program initiated to develop high-yielding cultivars of wheat for producers in the area. In 1965, the Centro Internationale de Mejoramiento de Maiz y Trigo (CIMMYT) was established in Mexico, as the second of the currently 16 International Agricultural Research Centers (IARCs) by the Consultative Group on International Agricultural Research (CGIAR). The purpose of the center was to undertake wheat and maize research to meet the production needs of developing countries. Dr Borlaug served as the director of the Wheat Program at CIMMYT until 1979 when he retired from active research, but not until he had accomplished his landmark achievement, dubbed the Green Revolution. The key technological strategies employed by Dr Borlaug and his team were to develop high-yielding varieties of wheat, and an appropriate agronomic package (fertilizer, irrigation, tillage, pest control) for optimizing the yield potential of the varieties. Adopting an interdisciplinary approach, the team assembled germplasm of wheat from all over the world. Key contributors to the efforts included Dr Burton Bayles and Dr Orville Vogel, both of the USDA, who provided the critical genotypes used in the breeding program. These genotypes were crossed with Mexican genotypes to develop lodging-resistant, semidwarf wheat varieties that were adapted to the Mexican production region (Figure 1). Using the improved varieties and appropriate agronomic packages, wheat production in Mexico increased dramatically from its low 750 kg/ha to about 3,200 kg/ha. The successful cultivars were introduced into other parts of the world, including Pakistan, India, and Turkey in 1966, with equally dramatic results. So successful was the effort in wheat that the model was duplicated in rice in the Philippines in 1960. In 1970, Dr Norman Borlaug was honored with the Nobel Peace Prize for contributing to curbing hunger in Asia and other parts of the world where his improved wheat varieties were introduced (Figure 2). Whereas the Green Revolution was a life-saver for countries in Asia and some Latin American countries, another part of the world that is plagued by periodic food shortages, the sub-Saharan Africa, did not beneﬁt from this event. After retiring from CIMMYT in 1979, Dr Borlaug focused his energies on alleviating hunger and promoting the general well-being of the people on the continent of Africa. Unfortunately, this time around, he had to go without the support of these traditional allies, the Ford Foundation, the Rockefeller Foundation, and the World Bank. It appeared the activism of powerful environmental groups in the developed world had managed to persuade these donors from supporting what, in their view, was an environmentally intrusive practice advocated by people such at Dr Borlaug. These environmentalists promoted the notion that high-yield agriculture for Africa, where the agronomic package included inorganic fertilizers, would be ecologically disastrous. Incensed by the distractions of “green politics”, which sometimes is conducted in an elitist fashion, Dr Borlaug decided to press on undeterred with his passion to help African farmers. At about the same time, President Jimmy Carter was collaborating with the POPC01 28/8/06 4:02 PM Page 12

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late Japanese industrialist, Ryoichi Sasakawa, in addressing some of the same agricultural issues dear to Dr Borlaug. In 1984, Mr Sasakawa persuaded Dr Borlaug to come out of retirement to join them to vigorously pursue food production in Africa. This alliance gave birth to the Sasakawa Africa Association, presided over by Dr Borlaug. In conjunction with Global 2000 of The Carter Center, Sasakawa-Global 2000 was born, with a mission to help small- scale farmers to improve agricultural productivity and crop quality in Africa. Without wasting time, Dr Borlaug selected an initial set of countries in which to run projects. These included Ethiopia, Ghana, Nigeria, Sudan, Tanzania, and Benin (Figure 3). The crops targeted included popular staples such as corn, cassava, sorghum, and cow- peas, as well as wheat. The most spectacular success was realized in Ethiopia, where the country recorded its highest ever yield of major crops in the 1995–1996 growing season. Sasakawa-Global 2000 operates in some 12 African nations. Dr Borlaug is still associated with CIMMYT and also holds a faculty position at Texas A&M University, where he teaches international agriculture in the fall semester. On March 29, 2004, in commemo- ration of his 90th birthday, Dr Borlaug was honored by the USDA with the establishment of the Norman E. Borlaug International Science and Technology Fellowship Program. The fellowship is designed to bring junior and mid-ranking scientists and policy- makers from African, Asian, and Latin American countries to the United States to learn from their US counterparts. Figure 1 Dr Norman Borlaug working in a wheat crossing block.

Figure 2 A copy of the actual certiﬁcate presented to Dr Norman Borlaug as part of the 1970 Nobel Peace Prize Award he received. POPC01 28/8/06 4:02 PM Page 13

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Further reading Borlaug, N.E. 1958. The impact of agricultural research on Mexican wheat production. Trans. New York Acad. Sci. 20:278–295. Borlaug, N.E. 1965. Wheat, rust, and people. Phytopathology 55:1088–1098. Borlaug, N.E. 1968. Wheat breeding and its impact on world food supply. Public lecture at the 3rd International Wheat Genetics Symposium, August 5–9, 1968. Australian Academy of Science, Canberra, Australia. Brown, L.R. 1970. Seeds of change: The Green Revolution and development in the 1970s. Praeger, New York. Byerlee, D., and P. Moya. 1993. Impacts of international wheat breeding research in the developing world. Mexico CIMMYT, El Batán, Mexico. Figure 3 Dr Twumasi Afriyie, CIMMYT Highland Maize Dalrymple, D.G. 1986. Development and spread of high-yielding rice varieties in developing countries. Breeder and a native of Ghana, discusses the quality protein Agency for International Development, Washington, maize he was evaluating in a farmer’s ﬁeld in Ghana with DC. Dr Borlaug. Haberman, F.W. 1972. Nobel lectures, 1951–1970. Nobel lectures, peace. Elsivier Publishing Company, Amsterdam. Wharton, C.R. Jr. 1969. The Green Revolution: cornu- copia or Pandora’s box? Foreign Affairs 47:464–476.

responsiveness to heavy fertilization. The short, stiff plement the improved genotype. This agronomic stalk of the improved dwarf cultivar resisted lodging package included tillage, fertilization, irrigation, and under heavy fertilization. Unimproved indigenous geno- pest control. types experienced severe lodging under heavy fertiliza- 3 Favorable returns on investment in technology. tion, resulting in drastic reduction in grain yield. A favorable ratio between the cost of fertilizer and Similarly, cereal production in Asia doubled between other inputs and the price the farmer received for 1970 and 1995, as the population increased by 60%. using this product was an incentive for farmers to Unfortunately, the beneﬁts of the Green Revolution adopt the production package. barely reached sub-Saharan Africa, a region of the world with perennial severe food shortages, partly because Not unexpectedly, the Green Revolution has been the of the lack of appropriate infrastructure and limited subject of some intensive discussion to assess its socio- resources. Dr Norman Borlaug received the 1970 Nobel logical impacts and identify its shortcomings. Incomes Prize for Peace for his efforts at curbing global hunger. of farm families were raised, leading to an increase in Three speciﬁc strategies were employed in the Green demand for goods and services. The rural economy was Revolution: energized. Food prices dropped. Poverty declined as agricultural growth increased. However, critics charge 1 Plant improvement. The Green Revolution cen- that the increase in income was inequitable, arguing tered on the breeding of high-yielding, disease- that the technology package was not scale neutral (i.e., resistant, and environmentally responsive (adapted, owners of larger farms were the primary adopters responsive to fertilizer, irrigation, etc.) cultivars. because of their access to production inputs – capital, 2 Complementary agronomic package. Improved seed, irrigation, fertilizers, etc.). Furthermore, the cultivars are as good as their environment. To realize Green Revolution did not escape the accusations the full potential of the newly created genotype, a often leveled at high-yielding agriculture – environ- certain production package was developed to com- mental degradation from improper or excessive use of POPC01 28/8/06 4:02 PM Page 14

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agrochemicals. Recent studies have shown that many of enced a slight decline in graduates in recent past. these charges are overstated. Because of the increasing role of biotechnology in plant genetic manipulation, graduates who com- bine skills and knowledge in both conventional and Future of plant breeding in society molecular technologies are in high demand. It has been observed that some commercial plant breeding For as long as the world population is expected to con- companies prefer to hire graduates with training in tinue to increase, there will continue to be a demand for molecular genetics, and then provide them with the more food. However, with an increasing population needed plant breeding skills on the job. comes an increasing demand for land for residential, 4 The key players in plant breeding industry. The last decade saw a fierce race by multinational pharma- commercial, and recreational uses. Sometimes, farm ceutical corporations to acquire seed companies. lands are converted to other uses. Increased food pro- There were several key mergers as well. The modern duction may be achieved by increasing production per technologies of plant breeding are concentrated in unit area or bringing new lands into cultivation. Some of the hands of a few of these giant companies. The the ways in which society will affect and be affected by trend of acquisition and mergers are likely to con- plant breeding in the future are as follow: tinue in the future. 5 Yield gains of crops. With the dwindling of arable 1 New roles of plant breeding. The traditional roles land and the increase in policing of the environment of plant breeding (food, feed, fiber, and ornamentals) by activists, there is an increasing need to produce will continue to be important. However, new roles more food or other crop products on the same piece are gradually emerging for plants. The technology for of land in a more efficient and environmentally safer using plants as bioreactors to produce pharmaceuti- manner. High-yielding cultivars will continue to be cals will advance; this technology has been around for developed, especially in crops that have received less over a decade. Strategies are being perfected for use attention from plant breeders. Breeding for adapta- of plants to generate pharmaceutical antibodies, engi- tion to environmental stresses (e.g., drought, salt) neering antibody-mediated pathogen resistance, and will continue to be important, and will enable more altering plant phenotypes by immunomodulation. food to be produced on marginal lands. Successes that have been achieved include the incor- 6 The biotechnology debate. It is often said that these poration of Streptococcus surface antigen in tobacco, modern technologies for plant genetic manipulation and the herpes simplex virus in soybean and rice. benefit the developing countries the most since they 2 New tools for plant breeding. New tools will be are in dire need of food, both in quantity and nutri- developed for plant breeders, especially, in the areas tional value. On the other hand, the intellectual of the application of biotechnology to plant breeding. property that covers these technologies is owned by New marker technologies continue to be developed the giant multinational corporations. Efforts will and older ones advanced. Tools that will assist breeders continue to be made to negotiate fair use of these to more effectively manipulate quantitative traits will technologies. Appropriate technology transfer and be enhanced. support to the poor third world nations will continue, 3 Training of plant breeders. As discussed elsewhere to enable them to develop capacity for the exploita- in the book, plant breeding programs have experi- tion of these modern technologies.

References and suggested reading

Charles, D., and B. Wilcox. 2002. Lords of the harvest: International Food Policy Research Institute. 2002. Green Biotechnology, big money and the future of food. Perseus Revolution – Curse or blessing? IFPRI, Washington, DC. Publishing, Cambridge, MA. Solheim, W.G., II. 1972. An earlier agricultural revolution. Duvick, D.N. 1986. Plant breeding: Past achievements and Sci. Am. 226(4):34–41. expectations for the future. Econ. Bot. 40:289–297. Zirkle, C. 1932. Some forgotten records of hybridization and Frey, K.J. 1971. Improving crop yields through plant breed- sex in plants. J. Heredity 23:443–448. ing. Am. Soc. Agron. Spec. Publ. 20:15–58. POPC01 28/8/06 4:02 PM Page 15

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Outcomes assessment

Part A Please answer the following questions true or false:

1 Plant breeding causes permanent changes in plant heredity. 2 Rice varieties were the ﬁrst products of the experiments leading to the Green Revolution. 3 Rice is high in pro-vitamin A. 4 The IR8 was the rice variety released as part of the Green Revolution. 5 Wilhelm Johannsen developed the pure-line theory.

Part B Please answer the following questions:

1 ………………...... …………….. won the Nobel Peace Prize in …...... …… for being the chief architect of the ……………………………………………………….. 2 Define plant breeding. 3 Give three specific objectives of plant breeding. 4 Discuss plant breeding before Mendel’s work was discovered. 5 Give the first two major wheat cultivars to come out of the Mexican Agricultural Program initiated in 1943.

Part C Please write a brief essay on each of the following topics:

1 Plant breeding is an art and a science. Discuss. 2 Discuss the importance of plant breeding to society. 3 Discuss how plant breeding has changed through the ages. 4 Discuss the role of plant breeding in the Green Revolution. 5 Discuss the impact of plant breeding on crop yield. 6 Plant breeding is critical to the survival of modern society. Discuss.